Backport: Load custom ITransformationServices from the classpath in dev (#8350)

fmlloader/src/main/java/net/minecraftforge/fml/loading/ClasspathLocatorUtils.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.fml.loading;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+public class ClasspathLocatorUtils {
+    
+    private static final Logger LOGGER = LogManager.getLogger();
+
+    public static Path findJarPathFor(final String resourceName, final String jarName, final URL resource) {
+        try {
+            Path path;
+            final URI uri = resource.toURI();
+            if (uri.getScheme().equals("jar") && uri.getRawSchemeSpecificPart().contains("!/")) {
+                int lastExcl = uri.getRawSchemeSpecificPart().lastIndexOf("!/");
+                path = Paths.get(new URI(uri.getRawSchemeSpecificPart().substring(0, lastExcl)));
+            } else {
+                path = Paths.get(new URI("file://"+uri.getRawSchemeSpecificPart().substring(0, uri.getRawSchemeSpecificPart().length()-resourceName.length())));
+            }
+            //LOGGER.debug(CORE, "Found JAR {} at path {}", jarName, path.toString());
+            return path;
+        } catch (NullPointerException | URISyntaxException e) {
+            LOGGER.fatal(LogMarkers.SCAN, "Failed to find JAR for class {} - {}", resourceName, jarName);
+            throw new RuntimeException("Unable to locate "+resourceName+" - "+jarName, e);
+        }
+    }
+}

fmlloader/src/main/java/net/minecraftforge/fml/loading/ClasspathTransformerDiscoverer.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.fml.loading;
+
+import cpw.mods.modlauncher.api.NamedPath;
+import cpw.mods.modlauncher.serviceapi.ITransformerDiscoveryService;
+import org.apache.logging.log4j.LogManager;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.*;
+
+public class ClasspathTransformerDiscoverer implements ITransformerDiscoveryService {
+
+    private final List<Path> legacyClasspath = Arrays.stream(System.getProperty("legacyClassPath", "").split(File.pathSeparator)).map(Path::of).toList();
+
+    @Override
+    public List<NamedPath> candidates(Path gameDirectory) {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public List<NamedPath> candidates(final Path gameDirectory, final String launchTarget) {
+        if (launchTarget != null && launchTarget.contains("dev")) {
+            this.scan(gameDirectory);
+        }
+        return List.copyOf(found);
+    }
+
+    private final static List<NamedPath> found = new ArrayList<>();
+
+    public static List<Path> allExcluded() {
+        return found.stream().map(np->np.paths()[0]).toList();
+    }
+    
+    private void scan(final Path gameDirectory) {
+        try {
+            locateTransformers("META-INF/services/cpw.mods.modlauncher.api.ITransformationService");
+            locateTransformers("META-INF/services/net.minecraftforge.forgespi.locating.IModLocator");
+        } catch (IOException e) {
+            LogManager.getLogger().error("Error during discovery of transform services from the classpath", e);
+        }
+    }
+
+    private void locateTransformers(String resource) throws IOException {
+        final Enumeration<URL> resources = ClassLoader.getSystemClassLoader().getResources(resource);
+        while (resources.hasMoreElements()) {
+            URL url = resources.nextElement();
+            Path path = ClasspathLocatorUtils.findJarPathFor(resource, url.toString(), url);
+            if (legacyClasspath.stream().anyMatch(path::equals) || !Files.exists(path) || Files.isDirectory(path))
+                continue;
+            found.add(new NamedPath(path.toUri().toString(), path));
+        }
+    }
+}

fmlloader/src/main/java/net/minecraftforge/fml/loading/moddiscovery/ClasspathLocator.java

@@ -5,18 +5,16 @@
 
 package net.minecraftforge.fml.loading.moddiscovery;
 
+import net.minecraftforge.fml.loading.ClasspathLocatorUtils;
 import net.minecraftforge.fml.loading.LogMarkers;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 import java.io.File;
 import java.io.IOException;
-import java.net.URI;
-import java.net.URISyntaxException;
 import java.net.URL;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Enumeration;
@@ -58,7 +56,7 @@ public class ClasspathLocator extends AbstractJarFileModLocator {
         final Enumeration<URL> resources = ClassLoader.getSystemClassLoader().getResources(resource);
         while (resources.hasMoreElements()) {
             URL url = resources.nextElement();
-            Path path = findJarPathFor(resource, resource, url);
+            Path path = ClasspathLocatorUtils.findJarPathFor(resource, resource, url);
             if (claimed.stream().anyMatch(path::equals) || !Files.exists(path) || Files.isDirectory(path))
                 continue;
             ret.add(path);
@@ -71,22 +69,4 @@ public class ClasspathLocator extends AbstractJarFileModLocator {
         var launchTarget = (String) arguments.get("launchTarget");
         enabled = launchTarget != null && launchTarget.contains("dev");
     }
-
-    private Path findJarPathFor(final String resourceName, final String jarName, final URL resource) {
-        try {
-            Path path;
-            final URI uri = resource.toURI();
-            if (uri.getScheme().equals("jar") && uri.getRawSchemeSpecificPart().contains("!/")) {
-                int lastExcl = uri.getRawSchemeSpecificPart().lastIndexOf("!/");
-                path = Paths.get(new URI(uri.getRawSchemeSpecificPart().substring(0, lastExcl)));
-            } else {
-                path = Paths.get(new URI("file://"+uri.getRawSchemeSpecificPart().substring(0, uri.getRawSchemeSpecificPart().length()-resourceName.length())));
-            }
-            //LOGGER.debug(CORE, "Found JAR {} at path {}", jarName, path.toString());
-            return path;
-        } catch (NullPointerException | URISyntaxException e) {
-            LOGGER.fatal(LogMarkers.SCAN, "Failed to find JAR for class {} - {}", resourceName, jarName);
-            throw new RuntimeException("Unable to locate "+resourceName+" - "+jarName, e);
-        }
-    }
 }

fmlloader/src/main/resources/META-INF/services/cpw.mods.modlauncher.serviceapi.ITransformerDiscoveryService

@@ -1 +1,2 @@
-net.minecraftforge.fml.loading.ModDirTransformerDiscoverer
+net.minecraftforge.fml.loading.ModDirTransformerDiscoverer
+net.minecraftforge.fml.loading.ClasspathTransformerDiscoverer